Donald



UNITED STATES PATENT OFFICE.

DAVID BARKER MACDONALD AND HANNIBAL VVILLIAM W'OODMAN, OF HAMILTON, ONTARIO, CANADA.

ELECTRIC LAM P.

PECIFICATION formng part of Letters Patent No. :339,908, dated April 13, 1886.

(No model.)

TO aZZ whom it may concern;

Be it known that we, DAVID BARKER MAc- DONALD and HANNIBAL WILLIAM WooDMAN, both of the city of Hamilton, in the county of lVentworth, in the Province of Ontario, Dominion of Canada, havejointly invented a certain new and useful Improvement in Electric-Are Lamps; and we do hereby declare that the following is a full, clear, and exact description of the construetion and operation of the same.

The invention relates to an improvement in electric-arc lamps by which all the devices heretofore used for regulating the feed of the carbons may be dispensed with, rendering an electric lamp much more simple and comparatively inexpensive.

The invention consists, first, in a device for controlling the length of the arc at the points of the carbons, or any substitute for carbons, by interposing a body or substance of any kind which will stand the heat between the carbon points, so that the said body will rest upon the lower carbon, and the point'of the upper carbon will rest upon the body, and by means of which the carbon points will always be the same distance apart, as the top one will feed down by its own weight to the lower one as the carbons are consumed; second, the interposing body placed between the points of the carbons maybe of any shape or form, and placed in any position to the carbon points, or any substitute 'for carbons, by placing the said body exactly between the points ol'` the carbons or to one side thereof in any convenient nanncr.

By reference to the drawings forming a part ol' this specitication it will be seen that Fignre l represents a very simple electric lamp; Fig. 2, a section of the upper and lower earbons with body interposed directly between the carbon points; Fig. 3, a similar view, but showing body cut in two and separated, but connected with the body interposed between two n''ns nt'tached to the upper and lower portions oi` the body. Fig. 4 is the interposing body detached from the carbon points.

A represents a very simple frame of a lamp y secured to any convenient holder, as A'.

B is a brass bushing.

C is a carbon rod.

D is the upper carbon, let into the carbon rod C, and secured in any convenient manner.

D' is the lower carbon, let into the lower carbon-holder, E.

F is an insulator under and around the positive binding-post G.

H is the negative binding-post.

I is the positive conducting-wire.

J is the negative conducting wire.

K is the interposing body placed between the two carbons D and-D'. It is formed with a central body,which may be globular or otherwise, and provided with npper and lower projecting-pins a a, made to enter the carbons, which are made hollow, or rather constrncted- With a central opening. c, running through their entire length, suffieiently large to receive the projecting pins a a of the body K.

It will be observed that the said body K may be cut in two through the center, as seen at Fig. 3, and two short arms, d d, secured to the npper and lower portions, respectively, of the body K, and have interposed between the said arms, at their outward ends, a body, K'. This means also prevents the upper carbon from touching the lower one as when the body K is interposed directly between the points of the carbon, as in Fg. 2.

It will further be observed that we do not confine ourselves to the particular manner in which the body K is made to separate the carbon points, two only of which are shown, as at Figs. 2 and 3.

Having thus described our device and its advantages, what we claim as our invention, and desire to secure by Letters Patent, is-

1. In an electric lamp, the eonbination, with the lower stationary carbon and the upper'movable carbon, located one above the other, of the insulating body K, interposed ing arms d d, fittingin the perforations in the c between the points of said ea'bons, said upearbons, substantially as described.

per carbon being constructed to rest by grav- Dated at Hamilton, Ontario. Canada, this i ity upon the interposed insulating-body, sub- 2d day of December, A. D. 1885. 5 stantially as described. DAVID BARKER MACDONALD.

2. In an electric lamp, the eombination, HANNIBAL WILLIAM WOODMAN. with the perfo'ated stationary lower carbon, In presence of- D', and the perforated upper movable earbon, JOHN KENRICK,

D, of the inte'posed insulating-body K, hav- WM. BRUOE. 

